The present invention relates to an electrostatic dust collector for use in a vacuum system and suitable for removing dust in a vacuum chamber having high-voltage electrodes, for example, an apparatus for producing electronic device such as semiconductors by forming thin films through utilization of vacuum or a high-frequency accelerating chamber of a particle accelerator.
Conventionally, electrostatic dust collectors for use in atmosphere have been widely used in various technical fields. However, no apparatus for removing dust in vacuum environment has been proposed. Thus, in the case where gas, etc. are fed into vacuum environment, a filter has been at most employed so as to minimize entry of dust into vacuum environment. In this case, the filter can achieve a rather excellent dust collecting effect. However, the filter cannot remove dust generated from an exhaust pump operated under vacuum environment, such as an ion pump, a titanium sublimation pump, etc. nor thin-layered dust adhering to a wall of a vacuum chamber. Thus, wafers of the semiconductors, an apparatus for producing the wafers, etc. are soiled with dust generated in vacuum environment. Hence, yield of the wafers, etc. drops and the exhaust pump also deteriorates. Meanwhile, dust is collected in the high-frequency accelerating chamber of the particle accelerator. Thus, if dust adheres to high-pressure components of the particle accelerator, abnormal electric discharge happens, thereby resulting in insufficient acceleration of particles.
Meanwhile, in the known electrostatic dust collectors for use in atmosphere, air or gas is passed between collecting electrodes such that dust in air or gas is caused to adhere to the collecting electrodes. Hence, the known electrostatic dust collectors cannot be used for removing dust adhering to the wall of the vacuum chamber or the wafers. In addition, even if dust is caused to adhere to the collecting electrodes, dust drops therefrom when electric charge of dust vanishes, so that cleaning in vacuum environment cannot be performed by the known electrostatic dust collectors.